The Greater Manchester Police responded to “reports of an explosion” at the Manchester Arena, where the pop superstar was performing as part of her “Dangerous Woman Tour.” “There are a number of confirmed fatalities and others injured,” tweeted authorities. “Please AVOID the area as first responders work tirelessly at the scene.”

Concertgoer Evie Brewster told The Daily Mail that an explosion sound had fans “screaming and running for the exit” shortly after Grande’s final song.

“We could hear the police and ambulance sirens,” added Brewster. “It was terrifying…There were thousands of people trying to get out at once. They were all screaming and crying. The whole place smelt smokey and burnt.”

Other concertgoers offered similar accounts, including popular Twitter user @PopCrave, who wrote: “I was at the Ariana Grande show in Manchester. When the show had finished there was an explosion, a moment of silence and people started running and screaming. It was terrifying. There are now armed police and helicopters at the arena. I’m stuck in the car park & shaken up.”

I was at the Ariana Grande show in Manchester. When the show had finished there was an explosion, a moment of silence and people started…

Grande has yet to publicly address the incident. However, fans and fellow artists including Nicki Minaj, Bruno Mars, and Katy Perry are sending their prayers to those affected by the tragedy. “My heart hurts for my sister, Ariana & every family affected by this tragic event in the U.K. Innocent lives lost. I’m so sorry to hear this,” tweeted Nicki.

My heart hurts for my sister, Ariana & every family affected by this tragic event in the U.K. Innocent lives lost. I'm so sorry to hear this

UPDATE: According to Greater Manchester Police, 19 people have been confirmed dead and around 50 others have been injured as a result of the explosion at Manchester Arena. Police are calling it a “terrorist incident,” while TMZ adds that it was a nail bomb that exploded “in the rotunda area near the front door as people were leaving the concert.”